Various types of microphone systems have been used in various applications through the years. Microphones in these systems typically receive acoustic energy and convert this acoustic energy into an electrical voltage. This voltage can be further processed by other applications or for other purposes. For example, in a hearing aid system the microphone may receive acoustic energy, and convert the acoustic energy to an electrical voltage. The voltage may be amplified or otherwise processed by an amplifier, or by other signal processing electronics circuitry, and then presented by a receiver as acoustic energy to a user or wearer of the hearing aid. To take another specific example, microphone systems in cellular phones typically receive sound energy, convert this energy into a voltage, and then this voltage can be further processed for use by other applications. Microphones are used in other applications and in other devices as well.
In such systems, it is typically important that the microphone is small. For instance, over the years cellular phones have become increasingly smaller, requiring smaller and smaller components. To that end, Microelectricalmechanical Systems (MEMS) are often used in microphones, which are often placed entirely inside an outer housing. More specifically, previous configurations for MEMS microphones consist of a distinct die placed inside a separate external box or inside larger, molded encasings which serve as bulk walls. In other words, the entire die is contained within a surrounding assembly.
However, since these previous assemblies must hold the entire MEMS die and ASIC, their size typically remains relatively large. This has limited the size reductions that are possible with MEMS assemblies, which, in turn limits the size reductions possible in the device in which the assembly is disposed.
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